Monday, March 19, 2012

Dangers of Importing CAD into Revit

Importing and Linking CAD should be avoided. But why? And if it is unavoidable, how can I do it safely?
Here are some answers:

Potential Issus with Importing/Linking dwg (CAD) files into Revit

  • Corrupt dwg
  • Large file size and extraneous information
  • Linked CAD can become unlinked but will still display. This can cause confusion as to what the latest file is.
  • Possibility of someone exploding, causing up to 10,000 extra elements.
  • Many AutoCAD layers and linetypes are brought in after an explode
  • Size of CAD needs to be under 20miles in diameter. There can be items which are not part of the primary drawing that are very far away from 0.
  • Visual clutter
  • dwg files from programs like AutoCAD Architecture and Civil 3D may need special plugins to see all of the data.

More Issues...

What Can be Done

In AutoCAD:
Wblock only necessary information

In Revit:
Always link, don't import
Current View Only (for 2D dwgs)
Detailed explanation here for Survey drawings

Importing  and Linking CAD Best Practices part 1
Importing  and Linking CAD Best Practices part 2

Imported 3D AutoCAD not Sectioning


Troy Gates said...

Some more tips.

Put the DWG into an empty Revit file and link that into your main Revit model.

Put DWGs into their own worksets so you can toggle whether to show in all views or not.

Pin linked DWGs so they don't get moved around.

To prevent selecting of DWGs when using a crossing window, put them in their own design option.

Al Gore said...

Your so right Jay, the apsolute worst is when a dwg gets exploded in your model. Its like a bomb going off.

Anonymous said...

Possibility of someone exploding! Wait, oh. Whew, for a moment there, I thought that there was the possibility that I would actually explode if I made the foolish decision to import autoCAD to Revit.

charles boyd said...

Okay but if I didn't set up this file and a 3d dwg was imported instead of links, how do i update it without deleting and reinserting it?
Since it's not linked, I can't use manage links.

charles boyd said...

Okay but if a 3d dwg was imported instead of linked (i know i know. i didn't set up the file), how can i reload it without deleting and reinserting it? I don't want to have to redo all the visibility settings in all the views but since it was imported it doesnt show up in manage links.

Denese Couch said...

I'm actually looking for some help/advice. Working on a project for school and I have already drawn my 2-story house in AutoCAD and need to import it into Revit so I can create the model. I didn't have any problems importing level 1, however, when I tried to import level two, I keep getting this message: "Some elements were lost during import. ActiveX and some proprietary components cannot be imported." Then it goes on to suggest that I try exploding the file in AutoCAD or setting the PROXYGRAPHICS to 1. I have done all of this and none of it has worked. Does anyone have any other ideas?

Anonymous said...

Make sure you don't have any layout. Sometimes it cause problems. Delete all layouts and purge the drawing. Also has said up there make an wblock. Might solve the problem.

Anonymous said...

We have had so many problems with Autocad linking or importing because the file sizes in autocad are too large. Seems anything over 3 meg is slow in loading, 10 meg freezes Revit. Purge, DXFOUT, purge after opeing DXF and save as autocad works to reduce size so imports and links into Revit are fast.
TL Revit MEP user